<!DOCTYPE html>
<title>CSS Anchor Positioning: position-area positioning with additional insets</title>
<link rel="help" href="https://drafts.csswg.org/css-anchor-position/#position-area">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<!-- The grid:

          100      150      150
      +--------+--------+--------+
      |        |        |        |
  150 |        |        |        |
      |        |        |        |
      +--------+--------+--------+
      |        |        |        |
   75 |        |        |        |
      |        |        |        |
      +--------+--------+--------+
      |        |        |        |
  175 |        |        |        |
      |        |        |        |
      +--------+--------+--------+

  -->
<style>
  #container {
    position: absolute;
    width: 400px;
    height: 400px;
  }
  #anchored {
    position: absolute;
    align-self: stretch;
    justify-self: stretch;
    position-anchor: --anchor;
  }
  #anchor {
    margin-top: 150px;
    margin-left: 100px;
    width: 150px;
    height: 75px;
    anchor-name: --anchor;
  }
</style>
<div id="container">
  <div id="anchored"></div>
  <div id="anchor"></div>
</div>
<script>
  function test_position_area(position_area, insets, expected_offsets) {
    anchored.style.positionArea = position_area;
    for (const [prop, value] of Object.entries(insets)) {
      anchored.style[prop] = value;
    }

    test(() => {
      assert_equals(anchored.offsetLeft, expected_offsets.left, "Check expected offsetLeft");
      assert_equals(anchored.offsetTop, expected_offsets.top, "Check expected offsetTop");
      assert_equals(anchored.offsetWidth, expected_offsets.width, "Check expected offsetWidth");
      assert_equals(anchored.offsetHeight, expected_offsets.height, "Check expected offsetHeight");
    }, "Offsets for position-area: " + position_area + " and insets: " + JSON.stringify(insets));
  }

  test_position_area("span-all", {top:"5px", bottom:"5px", left:"5px", right:"5px"},
                  {left:5, top:5, width:390, height:390});

  test_position_area("center center", {top:"10px", bottom:"40px", left:"5px", right:"15px"},
                  {left:105, top:160, width:130, height:25});

  test_position_area("left bottom", {top:"10px", bottom:"40px", left:"5px", right:"15px"},
                  {left:5, top:235, width:80, height:125});

  test_position_area("span-right center", {top:"20%", bottom:"auto", left:"auto", right:"25%"},
                  {left:100, top:165, width:225, height:60});

  // No implicit anchor means the position-area should not apply, but the insets still should.
  anchored.style.positionAnchor = "auto";
  test_position_area("bottom right", {left:"50px", right:"100px", top:"30px" , bottom:"10px"},
                  {left:50, top:30, width:250, height:360});
</script>
